1. Field of the Invention
The present invention relates generally to wave energy beam transmission and detection equipment. The present invention relates more specifically to the use of such equipment for the detection and monitoring of the presence or absence of a person from a medical bed, chair, or other supportive structure so as to ensure the safety of a patient occupying such a structure.
2. Description of the Related Art
A problem well known to medical service providers is that of making sure certain patients remain in their hospital bed. Reasons for this include the need to quickly locate the patient, administer medical treatment to the correct patient, and the prevention of patient injury. Such knowledge is particularly important when patients have become disoriented due to illness or medication.
Medical bed and chair occupancy monitoring systems have been devised to assist medical providers with monitoring the presence or absence of a person in their bed. Such systems typically are equipped with an alarm or are electronically tied to a common monitoring location such as a nurse's station. Such systems principally use some form of pressure-sensitive switch as their key sensing element. U.S. Pat. Nos. 4,484,043 and 4,565,910, both by Musick et al., describe switch mechanisms which are used to open and close a circuit to indicate the evacuation of a bed by a patient. In the Musick et al. patents, the switch apparatus is housed in a thin, rectangular cover which may be placed between the patient and the mattress or underneath the mattress. The switch devices in the Musick patents are each comprised of two rectangular conductors which run the length of the device, are parallel to each other and lie one on top of the other. The two conductors are separated at both ends by a pliable material such as foam, and are held apart from each other through the rigidity of the switching apparatus itself. The switch is activated by the pressure of the patient's body weight on the device, either directly thereon or indirectly through the mattress. Once this weight is applied, the two conductive elements come into contact, the switch is closed, and the system indicates that the patient is in the bed. When the switch is opened by the absence of the patient's weight in the bed, the system then sounds an alarm or sends a signal to the medical facility call system through an appropriate interface.
Such pressure-sensitive switching elements, as previously described, suffer from certain inherent problems. Switching elements which are placed under the mattress exhibit extremely limited sensitivity and selectivity in identifying the presence of the patient in the bed. This is due to the fact that the patient's weight in the bed is masked by the mattress itself. This masking effect tends to result in frequent false alarms due to the switch failing to close properly, as well as the failure to generate an alarm when the switch fails to open even though the patient is no longer in the bed. As for pressure-sensitive switches placed between the patient and the mattress, they must be extremely thin to afford the patient a reasonable degree of comfort. Although such switches exhibit substantially improved sensitivity and selectivity, the required thinness of the switch elements causes them to have considerably limited life. Such switches are, therefore, manufactured as disposable devices whose costs prohibit their broad acceptance and use.
It is, therefore, an object of this invention to provide a reflectable wave energy beam device, which replaces the existing pressure-sensitive switches previously described for the monitoring of the presence of a patient in a medical environment. A further object of this invention is to provide such a device which either interfaces with occupancy monitoring control modules already in use or utilizes self-contained control module circuitry and controls.
It is another object of the present invention to provide a reflectable wave energy beam device which may be used as a portable unit or may be built into or mounted on a medical bed, chair or similar structure to sense the presence or absence of a person normally occupying the structure.
It is a further object of the present invention to provide a proximity monitoring device with a limited and controlled range that can reliably detect the presence or absence of a person, thereby decreasing the number of false and unreliable alarms.
It is another object of the present invention to provide a proximity monitoring device which will eliminate patient discomfort by replacing mechanical pressure-sensitive switches in the medical bed or chair with a remotely produced and remotely sensed wave energy beam.
It is a further object of this invention to provide a proximity monitoring device which will be unaffected by patient incontinence and the association infection control concerns, static electrical build-up, or pressure-sensitive switch element degradation, as suffered by systems presently in use.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.